Long before DNA was discovered and recognized as the genetic material of living things, researchers understood the basics of how traits are passed from parent to child and from generation to generation. This was largely due to the contributions of an Austrian monk, Gregor Mendel (1822-1884). Mendel is considered the father of genetics because he was the first to understand how genetic traits are passed from one generation to the next.

In 1856, Mendel, a monk at the Abbey of St. Thomas in Brno and later its abbot, began breeding and cultivating varieties of the garden pea plant, Pisum sativum, in an experimental garden on the abbey grounds. Mendel bred 34 varieties of the plants and kept detailed records of the variations that appeared when plants with different physical features were crossed. He eventually identified seven characteristics in the pea plants that were inherited by successive generations in predictable ways. He developed seven pure lines of garden peas with these traits, which included features like seed color, plant height, and pea pod shape. These traits were passed on from plant parents through what Mendel called "factors." We now know that these factors are actually genes.